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Spinning of Large Airplanes

Description: Report discusses the problem of large airplanes spinning and the fact that they should not be intentionally spun because they are not designed for the loads and speeds that may be encountered in spin and recovery. Stall and spin characteristics for large airplanes are described. Recommended piloting procedures in case of a large airplane spinning event are also provided.
Date: October 1944
Creator: Seidman, Oscar
Partner: UNT Libraries Government Documents Department
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Comparison of tightness of 78 degrees machine-countersunk rivets driven in holes prepared with 78 degrees and 82 degrees countersinking tools

Description: Report presenting an investigation to determine whether the use of a 78 degree countersinking tool instead of a 82 degree countersinking tool for riveting would substantially alter the conclusion reached in a previous paper regarding the placement of rivets for maximum strength.
Date: September 1942
Creator: Gottlieb, Robert & Mandel, Merven W.
Partner: UNT Libraries Government Documents Department
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A simplified chart for determining Mach number and true airspeed from airspeed-indicator readings

Description: "The determination of flight Mach number from measurements of indicated airspeed and pressure altitude is shown to be relatively simple and leads to direct and accurate computation of true airspeed. A simplified chart is presented for determining flight Mach number and true airspeed for a range of values of indicated airspeed, pressure altitude, and air temperature. A table of standard atmospheric values is included" (p. 1).
Date: March 1943
Creator: Baals, Donald D. & Ritchie, Virgil S.
Partner: UNT Libraries Government Documents Department
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A Preignition Indicator for Aircraft Engines

Description: Report describes an electrical-relay circuit that uses cylinder thermocouples for indicating preignition or misfiring in an aircraft engine. The potential dangers of preignition and the importance of an easy-to-use, practical preignition indicator are provided. The operating principles of the indicator and a description of its functioning, calibration, and installation procedures are also included.
Date: February 1945
Creator: Dallas, Thomas & Harries, Myron L.
Partner: UNT Libraries Government Documents Department
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Effects of Compressibility and Large Angles of Yaw on Pressure Indicated by a Total-Pressure Tube

Description: Report discusses the effects of compressibility and angle of yaw on the pressure measured by a round-nose and a flat-nose total-pressure tube. The error incurred in the pressure measurements and factors affecting the total-pressure area are described.
Date: April 1945
Creator: Humphreys, Milton D.
Partner: UNT Libraries Government Documents Department
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Computation of the Mean Tangential Velocity of the Air Leaving the Blade Tips of a Centrifugal Supercharger

Description: Report discusses the differences between the mean tangential velocity of the air leaving the blade tips of a centrifugal supercharger calculated by the conventional turbine equation and by an equation that uses the isentropic increase in total enthalpy. The velocities are compared to experimental values observed with three diffusers.
Date: August 1945
Creator: Brown, W. Byron
Partner: UNT Libraries Government Documents Department
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A Method for the Determination of Aromatics in Hydrocarbon Mixtures

Description: Bulletin discusses a method to estimate aromatic hydrocarbons in hydrocarbon mixtures, which is important for determining the percentage of aromatics in fuel blends. The method was tested with nine base stocks at several levels of aromatics concentration and the maximum level of error was found to be about 0.5 percent. The speed and simplicity of the testing is emphasized.
Date: December 1945
Creator: Hipsher, Harold F.
Partner: UNT Libraries Government Documents Department
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Early Detection of Cracks Resulting From Fatigue Stressing

Description: Report discusses an apparatus that may be used for indicating the formation of fatigue cracks or for following the progress of cracks. Details of the experiment and discussion of the way in which the deflection-crack area relationship may be used to monitor fatigue cracks are included.
Date: September 1944
Creator: Bennett, John A.
Partner: UNT Libraries Government Documents Department
open access

Heat-Capacity Lag in Turbine-Working Fluids

Description: Report discusses measurements of the relaxation time of steam and nitrogen due to their importance as turbine-working fluids. Additional calculations regarding different nozzle lengths are included.
Date: May 1944
Creator: Kantrowitz, Arthur & Huber, Paul W.
Partner: UNT Libraries Government Documents Department
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Material Properties of Two Types of Plastic-Bonded Glass Cloth

Description: Report discusses the results of tensile and compressive tests of two types of plastic-bonded glass cloth and their potential use in aircraft construction. The ultimate tensile stress and compressive yield stresses for the different materials are provided.
Date: December 1944
Creator: Rafel, Norman & Schuette, Evan H.
Partner: UNT Libraries Government Documents Department
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Effect of Varying Percentages of Exhaust Gas on Engine Performance

Description: "These tests were run to determine the effect that mixing engine exhaust gas with engine intake air has on fuel knock limit, specific fuel consumption, and air consumption." Information about the effect on pressure, air consumption, and fuel consumption is detailed.
Date: April 1943
Creator: Sanders, Newell D. & Barnett, Henry C.
Partner: UNT Libraries Government Documents Department
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The Preparation of 2, 2, 4, 4-Tetramethylpentane

Description: Report presenting seven distinct operations in the preparation of 2,2,4,4-tetramethylpentane, including the preparation of di-isobutylene hydrochloride, preparation of dimethylzinc, reaction of dimethylzinc in dry benzene with di-isobutylene hydrochloride, preliminary distillation of the reaction products, treatment of the first distillate with sodium and alcohol, final distillation after appropriate washing of the products, and recovery of the iodine in the zinc residues of II as methyl iodide. more
Date: May 1942
Creator: Drake, N. L.
Partner: UNT Libraries Government Documents Department
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Determination of desirable lengths of Z- and channel-section columns for local-instability tests

Description: From Summary: "Local-instability tests of 24S-T aluminum-alloy formed Z- and channel-section columns were made in order to determine a length of test specimen that would avoid the increased strength associated with short lengths and also permit the occurrence of a convenient buckling pattern. The effect of column length on the critical compressive stress, on the average stress at maximum load, and on the number of half-waves of the buckling pattern is shown."
Date: October 1944
Creator: Heimerl, George J. & Roy, J. Albert
Partner: UNT Libraries Government Documents Department
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Tests of 10 Inch 24S-T Aluminum-Alloy Shear Panels With 1-1/2 Inch Holes 2: Panels Having Holes With Notched Edges

Description: Report discusses the results of testing of 10-inch 24S-T aluminum alloy shear panels with 1.5 inch holes with notched edges to determine if a notch decreases the strength of the panel and if reinforcements can overcome the negative effects of the notch. The notch did appear to increase the stress concentration around the holes, but the lack of applicability to real-world scenarios is discussed.
Date: April 1944
Creator: Kuhn, Paul & Levin, L. Ross
Partner: UNT Libraries Government Documents Department
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The Effect of Artificial Aging on the Tensile Properties of Alclad 24S-T and 24S-T Aluminum Alloy

Description: "An experimental study was made to determine the effect of artificial aging on the tensile properties of alclad 24S-T and 24S-T aluminum-alloy sheet material. The results of the tests show that certain combinations of aging time and temperature cause a marked increase in the yield strength and a small increase in the ultimate strength; these increases are accompanied by a very large decrease in elongation. A curve is presented that shows the maximum yield strengths that can be obtained by aging… more
Date: August 1943
Creator: Kotanchik, Joseph N.; Woods, Walter & Zender, George W.
Partner: UNT Libraries Government Documents Department
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The Effect of Angle of Bend Between Plate Elements on the Local Instability of Formed Z-Sections

Description: "Thirty-nine Z-sections formed from 24S-T aluminum-alloy sheet with the angle of bend between the flanges and the web varying from 5 degrees to 120 degrees were tested as columns. Angles of bend from 30 degrees to 120 degrees had little or no effect on the critical stress or on the average stress at maximum load for local instability of the columns. The lengths of the columns were such that at angles of bend below 30 degrees they failed by Euler buckling" (p. 1).
Date: September 1944
Creator: Roy, J. Albert & Schuette, Evan H.
Partner: UNT Libraries Government Documents Department
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The Longitudinal Shear Strength Required in Double-Angle Columns of 24S-T Aluminum Alloy

Description: "Tests were made of riveted double-angle columns to determine the total rivet strength that is required to make these built-up columns develop the strength predicted by the standard column formulas. Results of the tests led to the conclusion that the required rivet strength may be calculated by the beam method of design" (p. 1).
Date: May 1943
Creator: Kuhn, Paul & Moggio, Edwin M.
Partner: UNT Libraries Government Documents Department
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Tests of 10-Inch 24S-T Aluminum-Alloy Shear Panels With 1-1/2-Inch Holes

Description: Report discusses the results of testing on "10-inch shear panels of 24S-T aluminum alloy with 1.5 inch holes to determine the stress concentration at static rupture and the deformation characteristics" (from Summary). The strength of the perforated specimens is compared to the solid specimens and the critical stresses are computed. The stress at which permanent set occurs was also measured.
Date: June 1943
Creator: Kuhn, Paul & Levin, L. Ross
Partner: UNT Libraries Government Documents Department
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Pressure Lag in Tubing Used in Flight Research

Description: "Tests described in this report were undertaken to obtain a quantitative measure of the pressure lag in typical pressure-tubing systems used by the Ames Aeronautical Laboratory in flight research investigations. Lag measurements were made with both single-direction and oscillating pressure changes. Single-direction pressure changes were investigated to determine if the lag in orifice-pressure lines and in the research airspeed and altitude measuring systems of pursuit-type airplane undergoing f… more
Date: July 1945
Creator: Turner, Howard L. & Rathert, George A., Jr.
Partner: UNT Libraries Government Documents Department
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Effect of Normal Pressure on the Critical Compressive Stress of Curved Sheet

Description: Results are presented of tests of two specimens tested to study the effect of normal pressure on the critical compressive stress for thin curved sheets. These specimens are designated by their respective rib spacings of 10 inches and 30 inches. The relationship between compressive stress and normal pressure at which buckles disappeared is independent of whether the buckles were made to disappear by increase of normal pressure or decrease of compressive stress. (author).
Date: August 25, 1942
Creator: Rafel, Norman
Partner: UNT Libraries Government Documents Department
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